Measurement and Theoretical Study of Electrical Conductivity and Hall Effect in Oxide Cathodes

Abstract

Hall effect and electrical conductivity measurements have been made on the oxide cathode over the temperature range 500° to 1000°K. The Hall coefficient of the oxide cathode is negative and the Hall coefficient has a maximum value in the range 600° to 800°K. Above 700°K the values for electron mobility are very large, and below 700°K the mobility decreases rapidly with decreasing temperature. Large magneto-resistive effects were observed, and these were found to be dependent on the temperature and the degree of porosity of the cathode. These results are consistent with the porous semiconductor model for the oxide cathode as originally suggested by Loosjes and Vink. A mathematical theory, based on the high-temperature pore conductivity model, is developed which is in qualitative agreement with the data.